It is proposed to study transcriptional and translation regulation in the mammalian testis. Seqeunce diversities of RNA transcripts isolated from the prepuberal testis and from populations of isolated cell types will be analyzed to determine the extent of regulation at the transcriptional level during spermatogenesis. The temporal expression of specific polypeptides will be correlated to the timing of the synthesis of the encoding RNA to reveal translational regulatory processes. Special comparisons will be made of RNA transcripts from diploid and haploid cells to identify classes of messenger RNAs that may function in haploid gene expression. The repression of gene sequences in the haploid cell and the phenomenon of stored information in the form of "inactive" ribonucleoprotein particles will be examined. Hybrdization analysis will be used to definitively answer whether the ribosomal RNA genes are expressed in haploid cells. It is anticipated that these studies will provide RNA and protein markers specific to temporal events during spermatogenesis. These molecular markers will help elucidate two mechanisms by which gamete maturation is regulated in the testis.